Anonychomyrma geinitzi
| Anonychomyrma geinitzi Temporal range: Lutetian | |
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| Anonychomyrma geinitzi fossil | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hymenoptera |
| Family: | Formicidae |
| Genus: | Anonychomyrma |
| Species: | †A. geinitzi |
| Binomial name | |
| Anonychomyrma geinitzi (Mayr, 1868) | |
| Synonyms | |
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Anonychomyrma geinitzi is an extinct species of ant in the subfamily Dolichoderinae known from several Middle Eocene fossils found in Europe.[1] A. constricta is one of three species in the ant genus Anonychomyrma to have been described from fossils found in Baltic amber.[2]
History and classification
When first described, Anonychomyrma geinitzi was known from at least 168 separate fossils and by the time of the species' reexamination by Wheeler, at least 1041 specimens were known. The fossils include workers, females, males, larvae and pupae all of which are fossilized as inclusions in transparent chunks of Baltic amber.[1] Baltic amber is approximately forty six million years old, having been deposited during Lutetian stage of the Middle Eocene. There is debate on what plant family the amber was produced by, with evidence supporting relatives of either an Agathis relative or a Pseudolarix relative.[3] All the type specimens were collected over 125 years ago, and when first described were part of the University of Königsberg amber collection. The fossils were first studied by Austrian entomologist Gustav Mayr who placed the species in the genus Hypoclinea, now considered a junior synonym of the living genus Dolichoderus. Mayr's 1868 type description of the new species was published in the journal Beiträge zur Naturkunde Preussens.[1]
The species was moved from Hypoclinea to the small related genus Bothriomyrmex in 1873 by Dalla Torre. William Morton Wheeler in his 1915 paper The ants of the Baltic amber again moved the species, suggesting it would be better placed in the genus Iridomyrmex and noted it to be one of the most abundant ant species in the Baltic amber he had studied.[1] Wheeler based the placement on the structuring of the labial and maxillary palpi. This placement was unchallenged until the genus was reviewed and redefined and split up in 1992 by Steven Shattuck. In the review, Iridomyrmex was split into a more restricted genus group while the other species which did not match the definition were moved to other genera.[4] At that time Shattuck provisionally kept I. geinitzi in Iridomyrmex citing a lack of specimens for him to study. This placements was retained until 2011 when Shattuck and Brian Heterick again reviewed Iridomyrmex. With more fossils to study and based on a number of characters, the species was moved to the genus Anonychomyrma as A. geinitzi.[2] In addition to Anonychomyrma geinitzi, two other Anonychomyrma species are known from fossils, A. constricta and A. samlandica[2] both from Baltic, Bitterfeld and Rovno ambers. A. constricta and A. geinitzi have also both been identified from Scandinavian amber.[5]
Description
Overall Anonychomyrma geinitzi can be distinguished from the related Baltic amber species A. constricta in several ways. A. geinitzi individuals are overall more gracile in form with a less constricted mesonotum and the mesosoma has a less convex appearance. A. geinitzi specimens have maxillary palps which are six jointed, labial palps which are four jointed, and the clypeal border is sinuately indented in the middle. The pupae which Wheeler referred to the species are noted to not have any cocoon unlike the modern larvae of some ant subfamilies which will spin a cocoon to pupate in.[1] The eyes of A. geinitzi are placed more to the front and sides of he head capsule then seen in Iridomyrmex species.[2]
References
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- ↑ 1.0 1.1 1.2 1.3 1.4 Wheeler, W. M. (1915). "The ants of the Baltic amber". Schriften der Physikalisch-Okonomischen Gesellschaft zu Konigsberg 55 (4): 56–59.
- ↑ 2.0 2.1 2.2 2.3 Heterick, B. E.; Shattuck, S. (2011). "Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae)". Zootaxa 2845: 169.
- ↑ Henderickx, H.; Tafforeau, P.; Soriano, C (2012). "Phase-contrast synchrotron microtomography reveals the morphology of a partially visible new Pseudogarypus in Baltic amber (Pseudoscorpiones: Pseudogarypidae)". Palaeontologia Electronica 15 (2;17A,11p): 1–11.
- ↑ Shattuck, S. O. (1992). "Review of the dolichoderine ant genus Iridomyrmex Mayr with descriptions of three new genera (Hymenoptera: Formicidae)". Journal of the Australian Entomological Society 31: 13–18.
- ↑ Dlussky, G. M.; Rasnitsyn, A. P. (2009). "Ants (Insecta: Vespida: Formicidae) in the Upper Eocene Amber of Central and Eastern Europe". Paleontological Journal 43 (9): 1024–1042. doi:10.1134/S0031030109090056.